The arrangement of streets in the subdivision shall provide for the
continuation of the streets in adjoining subdivisions or for their
proper projection when adjoining property has not been subdivided,
insofar as in the judgment of the Planning Board such continuations
or projections are necessary for fire protection, for the proper movement
of traffic or for the construction or extension, presently or when
required, of needed utilities and public services, such as sewers,
water and drainage facilities. Where streets are continued, they shall
be at least as wide as the existing connecting streets, but never
less than 50 feet.